<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <input type="text" name="" id="" oninput="test();" onkeydown="test2();">

    <script>
        function test() {
            var $input = document.querySelector('input');
            console.log($input.value);
        }

        var count = 0;

        function test2() {
            console.log(`键盘被按下了${++count}次`);
        }
    </script>
</body>

</html>